[PATCH] drm/i915/vlv: Turn off power gate for BIOS-less system.

[Chon Ming Lee <chon.ming.lee@intel.com>]

During system boot up, by default, the power gate for render, media and
display well still power gated.  Normally, BIOS will turn off the power
gate.  In the BIOS-less system, the driver need to turn off the power
gate very early during driver load.

v2: Move this to intel_uncore_sanitize to allow it to get call during
resume path. (Daniel)
v3: Remove redundant write 0 to DPIO_CTL, and use DPIO_RESET instead of
just 0x1 (Ville)
    Add turn of power gate for display 2d/render well/media well.
v4: Remove toggle cmnreset in intel_uncore_sanitize.  Cmnreset should
toggle after CRI clock source has been selected.  Jesse DPIO reset patch
which toggle the cmnreset in intel_modeset_init_hw() should handle it.
(Ville)

Signed-off-by: Chon Ming Lee <chon.ming.lee@intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h     |    9 +++++++++
 drivers/gpu/drm/i915/intel_uncore.c |   16 ++++++++++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3432de4..f14310b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -361,6 +361,15 @@
 #define PUNIT_OPCODE_REG_READ			6
 #define PUNIT_OPCODE_REG_WRITE			7
 
+#define PUNIT_REG_PWRGT_CTRL			0x60
+#define PUNIT_REG_PWRGT_STATUS			0x61
+#define	  PUNIT_CLK_GATE			1
+#define	  PUNIT_PWR_RESET			2
+#define	  PUNIT_PWR_GATE			3
+#define	  RENDER_PWRGT				(PUNIT_PWR_GATE << 0)
+#define	  MEDIA_PWRGT				(PUNIT_PWR_GATE << 2)
+#define	  DISP2D_PWRGT				(PUNIT_PWR_GATE << 6)
+
 #define PUNIT_REG_GPU_LFM			0xd3
 #define PUNIT_REG_GPU_FREQ_REQ			0xd4
 #define PUNIT_REG_GPU_FREQ_STS			0xd8
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index f2753d9..288a3a6 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -301,10 +301,26 @@ static void intel_uncore_forcewake_reset(struct drm_device *dev)
 
 void intel_uncore_sanitize(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg_val;
+
 	intel_uncore_forcewake_reset(dev);
 
 	/* BIOS often leaves RC6 enabled, but disable it for hw init */
 	intel_disable_gt_powersave(dev);
+
+	/* Turn off power gate, require especially for the BIOS less system */
+	if (IS_VALLEYVIEW(dev)) {
+
+		mutex_lock(&dev_priv->rps.hw_lock);
+		reg_val = vlv_punit_read(dev_priv, PUNIT_REG_PWRGT_STATUS);
+
+		if (reg_val & (RENDER_PWRGT | MEDIA_PWRGT | DISP2D_PWRGT))
+			vlv_punit_write(dev_priv, PUNIT_REG_PWRGT_CTRL, 0x0);
+
+		mutex_unlock(&dev_priv->rps.hw_lock);
+
+	}
 }
 
 /*
-- 
1.7.7.6